A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first line because it introduces the main topic about language standards. It does not refer to any previous information. It sets the stage for the discussion without going into details. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'For example,' which is a conjunction. Paragraph 3 starts with 'This language,' which uses a pronoun that refers back to something else. Paragraph 4 starts with 'A pidgin,' which uses the definite article 'the' that assumes prior knowledge.

Concluding sentence: Why this is the last line? This paragraph is the last line because it provides a clear definition of a pidgin, which wraps up the discussion. It summarizes the main idea and gives a complete understanding of the topic.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives an example of the standard mentioned in Paragraph 1. This is a 'Topic Example' strategy.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it explains more about the language mentioned in Paragraph 2. This shows a 'Broader to Specific Strategy'.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it defines what a pidgin is, which is the topic of Paragraph 3. This is a 'Logical Order' strategy.